Medical and pharmacological personnel that are involved in the preparation and administration of hazardous drugs suffer the risk of being exposed to drugs and to their vapors, which may escape to the surroundings. As referred to herein, a “hazardous drug” is any injectable material the contact with which, or with the vapors of which, may constitute a health hazard. Illustrative and non-limitative examples of such drugs include, inter alia, cytotoxins, antiviral drugs, chemotherapy drugs, antibiotics, and radiopharmaceuticals, such as herceptin, cisplatinum, fluorouracil, leucovorin, taxol, metatroxat, gemzar, cyclophosphamide, cytoxan, and neosar, or a combination thereof, in a liquid, solid, or gaseous state.
Hazardous drugs in liquid or powder form are contained within vials, and are typically prepared in a separate room by pharmacists provided with protective clothing, a mouth mask, and a laminar flow safety cabinet. A syringe provided with a cannula, i.e. a hollow needle, is used for transferring the drug from a vial. After being prepared, the hazardous drug is added to a solution contained in a bag which is intended for parenteral administration, such as a saline solution intended for intravenous administration.
Since hazardous drugs are toxic, direct bodily contact thereto, or exposure to even micro-quantities of the drug vapors, considerably increases the risk of developing health fatalities such as skin cancer, leukemia, liver damage, malformation, miscarriage and premature birth. Such exposure can take place when a drug containing receptacle, such as a vial, bottle, syringe, and intravenous bag, is subjected to overpressure, resulting in the leakage of fluid or air contaminated by the hazardous drug to the surroundings. Exposure to a hazardous drug also results from a drug solution remaining on a needle tip, on a vial or intravenous bag seal, or by the accidental puncturing of the skin by the needle tip.
Some prior art liquid transfer devices are intended to provide contamination-free transfer of hazardous drugs.
For example, WO 2005/041846 discloses a drug mixing system comprising a receptacle port adaptor adapted to be inserted into a port of a fluid receptacle, a vial adaptor adapted for connection to a vial containing a drug, and a syringe adaptor attached to a syringe. The syringe adaptor is adapted to be brought into fluid communication and mechanically locked to at least one of the receptacle port adaptor and vial adaptor in an axial motion. When a user retracts the syringe plunger, fluid flows directly into the syringe, ensuring that the fluid remains sterile and that the user is not exposed to the fluid. The user is also not exposed to the fluid as the syringe adaptor is connected to, or disconnected from, the receptacle port adaptor or vial adaptor since the septum of the syringe adaptor is pushed into touching engagement with the corresponding septum of the receptacle port adaptor or vial adaptor, thereby preventing exposure of the syringe needle to the environment. The syringe adaptor comprises a septa housing, a compression spring seated within the septa housing, and a needle sealingly mounted within the housing and axially extending within the spring. The septa housing is movable relative to the needle in order to expose the needle tip.
This drug transfer system is an open system, which comprises a membrane vent and filter, for venting at least one of the receptacle port adaptor, the vial adaptor, and syringe adaptor to the atmosphere. After filtration, air contaminated by micro-quantities of the drug vapors is nevertheless exposed to the environment. Another disadvantage of this drug mixing system is that two septa are placed in mutual touching engagement by means of the biasing force of the spring. The biasing force applied by the spring is lower when the two septa are first placed in contact and increases as the septa are pierced by the needle. Consequently, any inadvertent movement of the system when the two septa are first placed in contact is liable to cause the two septa to be separated from each other and to cause a risk of exposure of the dangerous drug to the surroundings. An additional disadvantage of this system is that a securing device is engaged when the spring is fully compressed, and a release mechanism for manually disengaging the securing device is needed. In addition the system of the invention comprises a venting filter, which vents air that might be contaminated by vapors of the drug to the environment.
It would be desirable to provide a connector that causes two separated septa to be brought in locking engagement prior to a liquid transfer operation and to be separated following said operation without having to set a securing device or a release mechanism.
WO 02/11794, WO 03/086529, and U.S. Pat. No. 6,715,520 disclose a closed-system fluid transfer assembly for contamination-free drug transfer, i.e. without passage of a gas from the interior of a receptacle containing a hazardous drug to the surrounding environment. A connector to a drug bottle has a hollow needle for penetrating the closure of the drug bottle at a predetermined angle when establishing a fluid transfer line in a fluid transfer assembly. A connector locking member and membrane are included in a double membrane bayonet coupling with the fluid transfer device. A gas channel within the hollow needle transports gas from the bottle to a flexible container constituting a pressure compensator, and vice versa. The fluid transfer device comprises a syringe and a coupling unit. The coupling unit has a first part arranged for connection to the syringe and a second part arranged for connection to the drug bottle connector. The second part, which can be telescoped into the first part, is prevented from rising by a detent which slips into an opening of the first part and its locked position is released by an outwardly displaceable handle connected to the detent. After the drug is received in the fluid transfer device, an injection needle of the coupling unit penetrates a membrane of the injection port of a mixing device connected to the inlet port of an infusion bag. A spike member of an infusion line pierces the membrane of an outlet port of the mixing device without leakage.
This fluid transfer assembly requires a large number of steps in order to establish a connection by which a hazardous drug is transferred, including the steps of connecting the connector to the drug bottle, rotating and locking the coupling unit onto the syringe, lowering the coupling unit onto the connector, rotating and locking the coupling unit onto the connector, outwardly displacing the handle of the coupling unit, pressing on the fluid transfer assembly in order to retract the second part into the first part of the coupling unit, and manipulating the syringe. An additional disadvantage of this fluid transfer assembly is that a predetermined volume of air needs to be injected to the flexible container prior to a liquid transfer operation, in order to displace a corresponding volume of the drug from the vial; however, the volume of drug to be transferred, which is dependent on the volume of the injected air, cannot be adjusted by the health practitioner during a liquid transfer operation. An additional disadvantage of this fluid transfer assembly is that the air that needs to be injected prior to operation is taken from the environment and therefore involves the risk of introducing contaminants from the environment to the drug and violating its sterility.
Also, there is a risk that the flexible container, which is made of sheet material and is located externally to the syringe, may be punctured, thereby exposing the contaminated air to the environment and rendering the fluid transfer assembly inoperable. Furthermore, the sharp hollow needle of the drug bottle connector endangers, while remaining exposed to, a pharmacist until it penetrates the drug bottle closure. Consequently, this fluid transfer assembly cannot be considered within the group of safety products generally referred to as “needleless”, i.e. a transfer device having a sharp needle which is not exposed to a user. An additional disadvantage of this fluid transfer assembly is that an operator is liable to forget to perform one or more steps during the connection sequence, leading to the dangerous result that a double membrane seal will not be established. The dangerous drug will therefore be exposed to the surrounding air or is liable to be discharged from the syringe, thereby endangering the operator and bystanders.
It is an object of the present invention to provide a closed-system fluid transfer assembly that is adapted to prevent the leakage of a hazardous drug or air contaminated by the hazardous drug or drug vapors and prevents contaminants from the environment from coming into contact with the drug during the transfer process.
It is another object of the present invention to provide a closed-system fluid transfer assembly in which the same volume of the hazardous drug and air are exchanged internally by means of a pressure equalization arrangement within the fluid transfer assembly, thereby preventing any exposure of a user to the hazardous drug.
It is yet an additional object of the present invention to provide a fluid transfer assembly which does not expose any sharp objects such as the tip of a needle to a user during any stage of a fluid transfer operation.
Other objects and advantages of the invention will become apparent as the description proceeds.